gdb/frame.h

   1 /* Definitions for dealing with stack frames, for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1996,
   4    1997, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #if !defined (FRAME_H)
  24 #define FRAME_H 1
  25
  26 struct symtab_and_line;
  27
  28 /* The frame object.  */
  29
  30 struct frame_info;
  31
  32 /* The frame object's ID.  This provides a per-frame unique identifier
  33    that can be used to relocate a `struct frame_info' after a target
  34    resume or a frame cache destruct (assuming the target hasn't
  35    unwound the stack past that frame - a problem handled elsewhere).  */
  36
  37 struct frame_id
  38 {
  39   /* The frame's address.  This should be constant through out the
  40      lifetime of a frame.  */
  41   /* NOTE: cagney/2002-11-16: The ia64 has two stacks and hence two
  42      frame bases.  This will need to be expanded to accomodate that.  */
  43   CORE_ADDR base;
  44   /* The frame's current PC.  While the PC within the function may
  45      change, the function that contains the PC does not.  Should this
  46      instead be the frame's function?  */
  47   CORE_ADDR pc;
  48 };
  49
  50 /* For every stopped thread, GDB tracks two frames: current and
  51    selected.  Current frame is the inner most frame of the selected
  52    thread.  Selected frame is the one being examined by the the GDB
  53    CLI (selected using `up', `down', ...).  The frames are created
  54    on-demand (via get_prev_frame()) and then held in a frame cache.  */
  55 /* FIXME: cagney/2002-11-28: Er, there is a lie here.  If you do the
  56    sequence: `thread 1; up; thread 2; thread 1' you loose thread 1's
  57    selected frame.  At present GDB only tracks the selected frame of
  58    the current thread.  But be warned, that might change.  */
  59 /* FIXME: cagney/2002-11-14: At any time, only one thread's selected
  60    and current frame can be active.  Switching threads causes gdb to
  61    discard all that cached frame information.  Ulgh!  Instead, current
  62    and selected frame should be bound to a thread.  */
  63
  64 /* On demand, create the inner most frame using information found in
  65    the inferior.  If the inner most frame can't be created, throw an
  66    error.  */
  67 extern struct frame_info *get_current_frame (void);
  68
  69 /* Invalidates the frame cache (this function should have been called
  70    invalidate_cached_frames).
  71
  72    FIXME: cagney/2002-11-28: The only difference between
  73    flush_cached_frames() and reinit_frame_cache() is that the latter
  74    explicitly sets the selected frame back to the current frame there
  75    isn't any real difference (except that one delays the selection of
  76    a new frame).  There should instead be a get_selected_frame()
  77    method that reinit's the frame cache on-demand.  As for
  78    invalidating the cache, there should be two methods one that
  79    reverts the thread's selected frame back to current frame (for when
  80    the inferior resumes) and one that does not (for when the user
  81    modifies the target invalidating the frame cache).  */
  82 extern void flush_cached_frames (void);
  83 extern void reinit_frame_cache (void);
  84
  85 /* Select a specific frame.  NULL, apparently implies re-select the
  86    inner most frame.  */
  87 extern void select_frame (struct frame_info *);
  88
  89 /* Given a FRAME, return the next (more inner, younger) or previous
  90    (more outer, older) frame.  */
  91 extern struct frame_info *get_prev_frame (struct frame_info *);
  92 extern struct frame_info *get_next_frame (struct frame_info *);
  93
  94 /* Given a frame's ID, relocate the frame.  Returns NULL if the frame
  95    is not found.  */
  96 extern struct frame_info *frame_find_by_id (struct frame_id id);
  97
  98 /* Base attributes of a frame: */
  99
 100 /* The frame's `resume' address.  Where the program will resume in
 101    this frame.  */
 102 extern CORE_ADDR get_frame_pc (struct frame_info *);
 103
 104 /* Closely related to the resume address, various symbol table
 105    attributes that are determined by the PC.  Note that for a normal
 106    frame, the PC refers to the resume address after the return, and
 107    not the call instruction.  In such a case, the address is adjusted
 108    so that it (approximatly) identifies the call site (and not return
 109    site).
 110
 111    NOTE: cagney/2002-11-28: The frame cache could be used to cache the
 112    computed value.  Working on the assumption that the bottle-neck is
 113    in the single step code, and that code causes the frame cache to be
 114    constantly flushed, caching things in a frame is probably of little
 115    benefit.  As they say `show us the numbers'.
 116
 117    NOTE: cagney/2002-11-28: Plenty more where this one came from:
 118    find_frame_block(), find_frame_partial_function(),
 119    find_frame_symtab(), find_frame_function().  Each will need to be
 120    carefully considered to determine if the real intent was for it to
 121    apply to the PC or the adjusted PC.  */
 122 extern void find_frame_sal (struct frame_info *frame,
 123                             struct symtab_and_line *sal);
 124
 125 /* Return the frame address from FI.  Except in the machine-dependent
 126    *FRAME* macros, a frame address has no defined meaning other than
 127    as a magic cookie which identifies a frame over calls to the
 128    inferior (um, SEE NOTE BELOW).  The only known exception is
 129    inferior.h (PC_IN_CALL_DUMMY) [ON_STACK]; see comments there.  You
 130    cannot assume that a frame address contains enough information to
 131    reconstruct the frame; if you want more than just to identify the
 132    frame (e.g. be able to fetch variables relative to that frame),
 133    then save the whole struct frame_info (and the next struct
 134    frame_info, since the latter is used for fetching variables on some
 135    machines) (um, again SEE NOTE BELOW).
 136
 137    NOTE: cagney/2002-11-18: Actually, the frame address isn't
 138    sufficient for identifying a frame, and the counter examples are
 139    wrong!
 140
 141    Code that needs to (re)identify a frame must use get_frame_id() and
 142    frame_find_by_id() (and in the future, a frame_compare() function
 143    instead of INNER_THAN()).  Two reasons: an architecture (e.g.,
 144    ia64) can have more than one frame address (due to multiple stack
 145    pointers) (frame ID is going to be expanded to accomodate this);
 146    successive frameless function calls can only be differientated by
 147    comparing both the frame's base and the frame's enclosing function
 148    (frame_find_by_id() is going to be modified to perform this test).
 149
 150    The generic dummy frame version of PC_IN_CALL_DUMMY() is able to
 151    identify a dummy frame using only the PC value.  So the frame
 152    address is not needed.  In fact, most PC_IN_CALL_DUMMY() calls now
 153    pass zero as the frame/sp values as the caller knows that those
 154    values won't be used.  Once all architectures are using generic
 155    dummy frames, PC_IN_CALL_DUMMY() can drop the sp/frame parameters.
 156    When it comes to finding a dummy frame, the next frame's frame ID
 157    (with out duing an unwind) can be used (ok, could if it wasn't for
 158    the need to change the way the PPC defined frame base in a strange
 159    way).
 160
 161    Modern architectures should be using something like dwarf2's
 162    location expression to describe where a variable lives.  Such
 163    expressions specify their own debug info centric frame address.
 164    Consequently, a generic frame address is pretty meaningless.  */
 165
 166 extern CORE_ADDR get_frame_base (struct frame_info *);
 167
 168 /* Return the per-frame unique identifer.  Can be used to relocate a
 169    frame after a frame cache flush (and other similar operations).  */
 170 extern void get_frame_id (struct frame_info *fi, struct frame_id *id);
 171
 172 /* The frame's level: 0 for innermost, 1 for its caller, ...; or -1
 173    for an invalid frame).  */
 174 extern int frame_relative_level (struct frame_info *fi);
 175
 176 /* Return the frame's type.  Some are real, some are signal
 177    trampolines, and some are completly artificial (dummy).  */
 178
 179 enum frame_type
 180 {
 181   /* A true stack frame, created by the target program during normal
 182      execution.  */
 183   NORMAL_FRAME,
 184   /* A fake frame, created by GDB when performing an inferior function
 185      call.  */
 186   DUMMY_FRAME,
 187   /* In a signal handler, various OSs handle this in various ways.
 188      The main thing is that the frame may be far from normal.  */
 189   SIGTRAMP_FRAME
 190 };
 191 extern enum frame_type get_frame_type (struct frame_info *);
 192
 193 /* FIXME: cagney/2002-11-10: Some targets want to directly mark a
 194    frame as being of a specific type.  This shouldn't be necessary.
 195    PC_IN_SIGTRAMP() indicates a SIGTRAMP_FRAME and PC_IN_CALL_DUMMY()
 196    indicates a DUMMY_FRAME.  I suspect the real problem here is that
 197    get_prev_frame() only sets initialized after INIT_EXTRA_FRAME_INFO
 198    as been called.  Consequently, some targets found that the frame's
 199    type was wrong and tried to fix it.  The correct fix is to modify
 200    get_prev_frame() so that it initializes the frame's type before
 201    calling any other functions.  */
 202 extern void deprecated_set_frame_type (struct frame_info *,
 203                                        enum frame_type type);
 204
 205 /* Unwind the stack frame so that the value of REGNUM, in the previous
 206    (up, older) frame is returned.  If VALUEP is NULL, don't
 207    fetch/compute the value.  Instead just return the location of the
 208    value.  */
 209 extern void frame_register_unwind (struct frame_info *frame, int regnum,
 210                                    int *optimizedp, enum lval_type *lvalp,
 211                                    CORE_ADDR *addrp, int *realnump,
 212                                    void *valuep);
 213
 214 /* More convenient interface to frame_register_unwind().  */
 215 /* NOTE: cagney/2002-09-13: Return void as one day these functions may
 216    be changed to return an indication that the read succeeded.  */
 217
 218 extern void frame_unwind_signed_register (struct frame_info *frame,
 219                                           int regnum, LONGEST *val);
 220
 221 extern void frame_unwind_unsigned_register (struct frame_info *frame,
 222                                             int regnum, ULONGEST *val);
 223
 224 /* Get the value of the register that belongs to this FRAME.  This
 225    function is a wrapper to the call sequence ``frame_unwind_register
 226    (get_next_frame (FRAME))''.  As per frame_register_unwind(), if
 227    VALUEP is NULL, the registers value is not fetched/computed.  */
 228
 229 extern void frame_register (struct frame_info *frame, int regnum,
 230                             int *optimizedp, enum lval_type *lvalp,
 231                             CORE_ADDR *addrp, int *realnump,
 232                             void *valuep);
 233
 234 /* More convenient interface to frame_register().  */
 235 /* NOTE: cagney/2002-09-13: Return void as one day these functions may
 236    be changed to return an indication that the read succeeded.  */
 237
 238 extern void frame_read_signed_register (struct frame_info *frame,
 239                                         int regnum, LONGEST *val);
 240
 241 extern void frame_read_unsigned_register (struct frame_info *frame,
 242                                           int regnum, ULONGEST *val);
 243
 244 /* Map between a frame register number and its name.  A frame register
 245    space is a superset of the cooked register space --- it also
 246    includes builtin registers.  */
 247
 248 extern int frame_map_name_to_regnum (const char *name, int strlen);
 249 extern const char *frame_map_regnum_to_name (int regnum);
 250
 251 /* Unwind the PC.  Strictly speaking return the resume address of the
 252    calling frame.  For GDB, `pc' is the resume address and not a
 253    specific register.  */
 254
 255 extern CORE_ADDR frame_pc_unwind (struct frame_info *frame);
 256
 257 \f
 258 /* Return the location (and possibly value) of REGNUM for the previous
 259    (older, up) frame.  All parameters except VALUEP can be assumed to
 260    be non NULL.  When VALUEP is NULL, just the location of the
 261    register should be returned.
 262
 263    UNWIND_CACHE is provided as mechanism for implementing a per-frame
 264    local cache.  It's initial value being NULL.  Memory for that cache
 265    should be allocated using frame_obstack_alloc().
 266
 267    Register window architectures (eg SPARC) should note that REGNUM
 268    identifies the register for the previous frame.  For instance, a
 269    request for the value of "o1" for the previous frame would be found
 270    in the register "i1" in this FRAME.  */
 271
 272 typedef void (frame_register_unwind_ftype) (struct frame_info *frame,
 273                                             void **unwind_cache,
 274                                             int regnum,
 275                                             int *optimized,
 276                                             enum lval_type *lvalp,
 277                                             CORE_ADDR *addrp,
 278                                             int *realnump,
 279                                             void *valuep);
 280
 281 /* Same as for registers above, but return the address at which the
 282    calling frame would resume.  */
 283
 284 typedef CORE_ADDR (frame_pc_unwind_ftype) (struct frame_info *frame,
 285                                            void **unwind_cache);
 286
 287 /* Describe the saved registers of a frame.  */
 288
 289 #if defined (EXTRA_FRAME_INFO) || defined (FRAME_FIND_SAVED_REGS)
 290 /* XXXX - deprecated */
 291 struct frame_saved_regs
 292   {
 293     /* For each register R (except the SP), regs[R] is the address at
 294        which it was saved on entry to the frame, or zero if it was not
 295        saved on entry to this frame.  This includes special registers
 296        such as pc and fp saved in special ways in the stack frame.
 297
 298        regs[SP_REGNUM] is different.  It holds the actual SP, not the
 299        address at which it was saved.  */
 300
 301     CORE_ADDR regs[NUM_REGS];
 302   };
 303 #endif
 304
 305 /* We keep a cache of stack frames, each of which is a "struct
 306    frame_info".  The innermost one gets allocated (in
 307    wait_for_inferior) each time the inferior stops; current_frame
 308    points to it.  Additional frames get allocated (in
 309    get_prev_frame) as needed, and are chained through the next
 310    and prev fields.  Any time that the frame cache becomes invalid
 311    (most notably when we execute something, but also if we change how
 312    we interpret the frames (e.g. "set heuristic-fence-post" in
 313    mips-tdep.c, or anything which reads new symbols)), we should call
 314    reinit_frame_cache.  */
 315
 316 struct frame_info
 317   {
 318     /* Nominal address of the frame described.  See comments at
 319        get_frame_base() about what this means outside the *FRAME*
 320        macros; in the *FRAME* macros, it can mean whatever makes most
 321        sense for this machine.  */
 322     CORE_ADDR frame;
 323
 324     /* Address at which execution is occurring in this frame.
 325        For the innermost frame, it's the current pc.
 326        For other frames, it is a pc saved in the next frame.  */
 327     CORE_ADDR pc;
 328
 329     /* Level of this frame.  The inner-most (youngest) frame is at
 330        level 0.  As you move towards the outer-most (oldest) frame,
 331        the level increases.  This is a cached value.  It could just as
 332        easily be computed by counting back from the selected frame to
 333        the inner most frame.  */
 334     /* NOTE: cagney/2002-04-05: Perhaphs a level of ``-1'' should be
 335        reserved to indicate a bogus frame - one that has been created
 336        just to keep GDB happy (GDB always needs a frame).  For the
 337        moment leave this as speculation.  */
 338     int level;
 339
 340     /* The frame's type.  */
 341     enum frame_type type;
 342
 343     /* For each register, address of where it was saved on entry to
 344        the frame, or zero if it was not saved on entry to this frame.
 345        This includes special registers such as pc and fp saved in
 346        special ways in the stack frame.  The SP_REGNUM is even more
 347        special, the address here is the sp for the previous frame, not
 348        the address where the sp was saved.  */
 349     /* Allocated by frame_saved_regs_zalloc () which is called /
 350        initialized by FRAME_INIT_SAVED_REGS(). */
 351     CORE_ADDR *saved_regs;      /*NUM_REGS + NUM_PSEUDO_REGS*/
 352
 353 #ifdef EXTRA_FRAME_INFO
 354     /* XXXX - deprecated */
 355     /* Anything extra for this structure that may have been defined
 356        in the machine dependent files. */
 357       EXTRA_FRAME_INFO
 358 #endif
 359
 360     /* Anything extra for this structure that may have been defined
 361        in the machine dependent files. */
 362     /* Allocated by frame_obstack_alloc () which is called /
 363        initialized by INIT_EXTRA_FRAME_INFO */
 364     struct frame_extra_info *extra_info;
 365
 366     /* If dwarf2 unwind frame informations is used, this structure holds all
 367        related unwind data.  */
 368     struct context *context;
 369
 370     /* Unwind cache shared between the unwind functions - they had
 371        better all agree as to the contents.  */
 372     void *unwind_cache;
 373
 374     /* See description above.  The previous frame's registers.  */
 375     frame_register_unwind_ftype *register_unwind;
 376
 377     /* See description above.  The previous frame's resume address.
 378        Save the previous PC in a local cache.  */
 379     frame_pc_unwind_ftype *pc_unwind;
 380     int pc_unwind_cache_p;
 381     CORE_ADDR pc_unwind_cache;
 382
 383     /* Pointers to the next (down, inner, younger) and previous (up,
 384        outer, older) frame_info's in the frame cache.  */
 385     struct frame_info *next; /* down, inner, younger */
 386     int prev_p;
 387     struct frame_info *prev; /* up, outer, older */
 388   };
 389
 390 /* Values for the source flag to be used in print_frame_info_base(). */
 391 enum print_what
 392   {
 393     /* Print only the source line, like in stepi. */
 394     SRC_LINE = -1,
 395     /* Print only the location, i.e. level, address (sometimes)
 396        function, args, file, line, line num. */
 397     LOCATION,
 398     /* Print both of the above. */
 399     SRC_AND_LOC,
 400     /* Print location only, but always include the address. */
 401     LOC_AND_ADDRESS
 402   };
 403
 404 /* Allocate additional space for appendices to a struct frame_info.
 405    NOTE: Much of GDB's code works on the assumption that the allocated
 406    saved_regs[] array is the size specified below.  If you try to make
 407    that array smaller, GDB will happily walk off its end. */
 408
 409 #ifdef SIZEOF_FRAME_SAVED_REGS
 410 #error "SIZEOF_FRAME_SAVED_REGS can not be re-defined"
 411 #endif
 412 #define SIZEOF_FRAME_SAVED_REGS \
 413         (sizeof (CORE_ADDR) * (NUM_REGS+NUM_PSEUDO_REGS))
 414
 415 extern void *frame_obstack_alloc (unsigned long size);
 416 extern void frame_saved_regs_zalloc (struct frame_info *);
 417
 418 /* Define a default FRAME_CHAIN_VALID, in the form that is suitable for most
 419    targets.  If FRAME_CHAIN_VALID returns zero it means that the given frame
 420    is the outermost one and has no caller.
 421
 422    XXXX - both default and alternate frame_chain_valid functions are
 423    deprecated.  New code should use dummy frames and one of the
 424    generic functions. */
 425
 426 extern int file_frame_chain_valid (CORE_ADDR, struct frame_info *);
 427 extern int func_frame_chain_valid (CORE_ADDR, struct frame_info *);
 428 extern int nonnull_frame_chain_valid (CORE_ADDR, struct frame_info *);
 429 extern int generic_file_frame_chain_valid (CORE_ADDR, struct frame_info *);
 430 extern int generic_func_frame_chain_valid (CORE_ADDR, struct frame_info *);
 431 extern void generic_save_dummy_frame_tos (CORE_ADDR sp);
 432
 433
 434
 435 #ifdef FRAME_FIND_SAVED_REGS
 436 /* XXX - deprecated */
 437 #define FRAME_INIT_SAVED_REGS(FI) get_frame_saved_regs (FI, NULL)
 438 extern void get_frame_saved_regs (struct frame_info *,
 439                                   struct frame_saved_regs *);
 440 #endif
 441
 442 extern struct block *get_frame_block (struct frame_info *,
 443                                       CORE_ADDR *addr_in_block);
 444
 445 extern struct block *get_selected_block (CORE_ADDR *addr_in_block);
 446
 447 extern struct symbol *get_frame_function (struct frame_info *);
 448
 449 extern CORE_ADDR frame_address_in_block (struct frame_info *);
 450
 451 extern CORE_ADDR get_pc_function_start (CORE_ADDR);
 452
 453 extern struct block *block_for_pc (CORE_ADDR);
 454
 455 extern struct block *block_for_pc_sect (CORE_ADDR, asection *);
 456
 457 extern int frameless_look_for_prologue (struct frame_info *);
 458
 459 extern void print_frame_args (struct symbol *, struct frame_info *,
 460                               int, struct ui_file *);
 461
 462 extern struct frame_info *find_relative_frame (struct frame_info *, int *);
 463
 464 extern void show_and_print_stack_frame (struct frame_info *fi, int level,
 465                                         int source);
 466
 467 extern void print_stack_frame (struct frame_info *, int, int);
 468
 469 extern void print_only_stack_frame (struct frame_info *, int, int);
 470
 471 extern void show_stack_frame (struct frame_info *);
 472
 473 extern void print_frame_info (struct frame_info *, int, int, int);
 474
 475 extern void show_frame_info (struct frame_info *, int, int, int);
 476
 477 extern struct frame_info *block_innermost_frame (struct block *);
 478
 479 /* NOTE: cagney/2002-09-13: There is no need for this function.
 480    Instead either of frame_unwind_signed_register() or
 481    frame_unwind_unsigned_register() can be used.  */
 482 extern CORE_ADDR deprecated_read_register_dummy (CORE_ADDR pc,
 483                                                  CORE_ADDR fp, int);
 484 extern void generic_push_dummy_frame (void);
 485 extern void generic_pop_current_frame (void (*)(struct frame_info *));
 486 extern void generic_pop_dummy_frame (void);
 487
 488 extern int generic_pc_in_call_dummy (CORE_ADDR pc,
 489                                      CORE_ADDR sp, CORE_ADDR fp);
 490
 491 /* NOTE: cagney/2002-06-26: Targets should no longer use this
 492    function.  Instead, the contents of a dummy frames registers can be
 493    obtained by applying: frame_register_unwind to the dummy frame; or
 494    get_saved_register to the next outer frame.  */
 495
 496 extern char *deprecated_generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp);
 497
 498 extern void generic_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun,
 499                                     int nargs, struct value **args,
 500                                     struct type *type, int gcc_p);
 501
 502 /* The function generic_get_saved_register() has been made obsolete.
 503    GET_SAVED_REGISTER now defaults to the recursive equivalent -
 504    generic_unwind_get_saved_register() - so there is no need to even
 505    set GET_SAVED_REGISTER.  Architectures that need to override the
 506    register unwind mechanism should modify frame->unwind().  */
 507 extern void deprecated_generic_get_saved_register (char *, int *, CORE_ADDR *,
 508                                                    struct frame_info *, int,
 509                                                    enum lval_type *);
 510
 511 extern void generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi);
 512
 513 extern void get_saved_register (char *raw_buffer, int *optimized,
 514                                 CORE_ADDR * addrp,
 515                                 struct frame_info *frame,
 516                                 int regnum, enum lval_type *lval);
 517
 518 extern int frame_register_read (struct frame_info *frame, int regnum,
 519                                 void *buf);
 520
 521 /* From stack.c.  */
 522 extern void args_info (char *, int);
 523
 524 extern void locals_info (char *, int);
 525
 526 extern void (*selected_frame_level_changed_hook) (int);
 527
 528 extern void return_command (char *, int);
 529
 530
 531 /* NOTE: cagney/2002-11-27:
 532
 533    You might think that the below global can simply be replaced by a
 534    call to either get_selected_frame() or select_frame().
 535
 536    Unfortunatly, it isn't that easy.
 537
 538    The relevant code needs to be audited to determine if it is
 539    possible (or pratical) to instead pass the applicable frame in as a
 540    parameter.  For instance, DEPRECATED_DO_REGISTERS_INFO() relied on
 541    the selected_frame global, but its replacement,
 542    PRINT_REGISTERS_INFO(), is parameterized with the selected frame.
 543    The only real exceptions occure at the edge (in the CLI code) where
 544    user commands need to pick up the selected frame before proceeding.
 545
 546    This is important.  GDB is trying to stamp out the hack:
 547
 548    saved_frame = selected_frame;
 549    selected_frame = ...;
 550    hack_using_global_selected_frame ();
 551    selected_frame = saved_frame;
 552
 553    Take care!  */
 554
 555 extern struct frame_info *selected_frame;
 556
 557
 558 /* NOTE: cagney/2002-11-28:
 559
 560    These functions are used to explicitly create and set the inner
 561    most (current) frame vis:
 562
 563    set_current_frame (create_new_frame (read_fp(), stop_pc)));
 564
 565    Such code should be removed.  Instead that task can be left to
 566    get_current_frame() which will update things on-demand.
 567
 568    The only vague exception is found in "infcmd.c" (and a few
 569    architectures specific files) as part of the code implementing the
 570    command ``(gdb) frame FRAME PC''.  There, the frame should be
 571    created/selected in a single shot.  */
 572
 573 extern void set_current_frame (struct frame_info *);
 574 extern struct frame_info *create_new_frame (CORE_ADDR, CORE_ADDR);
 575
 576 #endif /* !defined (FRAME_H)  */